|
|
Senior Crew
Posts: 168
Location: St. John's, Newfoundland. | Subject: HPAC
I’m doing this for my own satisfaction. Yes, for the fun of it! I have never set foot on a Balao or sat in a classroom and I am doing this during my breaks at work and what little time I have at home. But the satisfaction I get is tremendous. My next input will complete the HPAC and then to the Receiving and Distribution Manifolds. I’ve been through much of this before but this is a good refresher.
Cheers guys, Hairball.
High Pressure Air – An Overview. Part One.
As the title states, this is an overview inasmuch as I want to simply demonstrate that I understand what the system does and why.
HP Air, what it’s for:
High Pressure air turns atmospheric air into a source of power for many of the boat’s systems.
Different Pressures:
There’s 5 Compressed Air systems four of which are sourced from the 3,000# system. The 10 Low Pressure Air is an independent system which uses an LP Compressor and is used when surfaced to blow any water left in the MBTs.
Pressures that start with a source of 3,000# air are: 3,000#, 600# MBT Blow, 225# Service Air all of which run everything from blowing the MBT’s, Torpedo Impulse Air and the Hydraulic System’s Accumulator and much besides.
HPAC – Normal Air Source:
‘Surface air,’ or that air which is drawn into the Pressure Hull when surfaced supplies the HPACs.
Salvage Source of HPAir:
The only source of 3,000# air other than that produced by the HPAC is the HP Air supplied by a surface vessel or dockside via the two HP Air Salvage connections externally located either side of the CT.
Safety Test:
The system is Hydrostatically tested to 4,500# which is 150% above max pressure.
HPAC – Brief Description:
The HPAC is a simple and reliable water-cooled pump that in many ways resembles an automobile engine. It has pistons, cylinders, a crank, crack-case etc. But instead of producing power it is powered by a direct-drive electric motor but unlike a car engine the HPAC is powered by a direct drive electric motor..
The HP Air Compressor is stepped up in 4 stages with the compressed air being cooled at each stgae - this is essential. The 4 Stages of Compression:
The HPAC is run when surfaced since when submerged the Pressure Hull is sealed. Atmospheric air enters the HPAC through a strainer/muffler and enters the:
FIRST STAGE where it’s pressure is raised between 31 to 38 psi and then passes through an Intercooler and then to the:
SECOND STAGE where the air pressure is raised to between 170 to 185 psi and again is cooled by an intercooler before going to the:
THIRD STAGE to an intercooler and then to the:
FOURTH STAGE where it reaches 3,000 psi and passes through the After cooler.
(Quote from Manual) Each compression stage is furnished with a safety valve, two thermometers, a pressure gage, a water separator, and a drain valve.
So the air goes through 4 stages of compression instead of being compressed in one cycle to 3,000 psi.
LUBRICATION – Oil is either force fed via adjustable knobs or by a pump that works from the Crankshaft. The pumped oil is filtered and cooled, lubricating all the bearings while the pressure fed oil lubricates the piston-rings cylinders and air valves (Chap 2C3 HP Air Sys. Online Boat Manual).
COOLING:
Similar to an automobile: There’s a Water Pump which cools the cylinders, the oil cooler, Intersooler and After cooler. After it has passed through the HOAC it is discharged overboard. (Paraphrase from Manual).
|
|
| |
|
Great Sage of the Sea
Posts: 892
Location: Palo Pinto County, Texas | Subject: RE: HPAC
Attaboy Aaron! Keep on trucking. Great to see you back on board and occasionally out of the bilges. Looks as though your studies are on-the-right-track. |
|
| |
|
Master and Commander
Posts: 1796
Location: Albany, GA. | Subject: RE: HPAC
I'm trying to figure out how to say this discretely. Most of us are used to a Non-Qual approaching with coffee and a sticky bun or doughnut hot from the grease. How you are going to manage that on this board will be interesting. As I have said before, I only sign aft of frame 85, so I personally am not much use to you. However there are others around here that did actually qualify on those iron lungs that probed the depths before Nuclear power took over. |
|
| |
|
COMSUBBBS
Posts: 6180
Location: Summerville, SC | Subject: RE: HPAC
Walt, you must remember and be very careful in how you phrase things with Hairball in the crowd. You must remember that he is a Ex Limey Airdale and the term "sticky buns", more than likely, has a different meaning.  
Hairball, ya done good mate!!!  Keep it up and progress on with some more. It sounds like you are getting to where you can picture the system in your mind and how simple and practical it is........I'm talking about the HPAC System, of course..... A what? |
|
| |
|
Plankowner
Posts: 9165
Location: Upper lefthand corner of the map. | Subject: RE: HPAC
OK, ya got me curious. Why you keeping the 3RD stage pressure secret? |
|
| |
|
COMSUBBBS
Posts: 2672
Location: New Jersey | Subject: RE: HPAC
Hairy,
Great summary.
This is a good refresher course for me...Nothing new about the different stages and assorted drains to remove water, but my mind lost all info about the different water & oil coolers.
Keep up the good work and before you know it, you may work yourself out of the bilges. Having said that, pull that main sea suction strainer and clean it out.... |
|
| |
|
COMSUBBBS
Posts: 6180
Location: Summerville, SC | Subject: RE: HPAC
And Hairy, while you're down there, it looks like the fuel filters need changing and while you're resting get some lube oil samples and start the lube oil purifier. Need to make some battery water before you get off watch too. |
|
| |
HPAC
